Piwi proteins and Piwi-interacting small RNAs (piRNAs) have known functions in transposon silencing in the male germline of fetal and newborn mice. Both are also necessary for spermatogenesis in adult testes, however, their function here remains a mystery. Here, we use germ cell isolations and small RNA sequencing to show that most piRNAs in meiotic spermatocytes originate from clusters in intergenic non-repeat regions of DNA. The regulation of these piRNA clusters, including the processing of the precursor transcripts into individual piRNAs, is accomplished through mostly unknown processes. We present evidence for a regulatory mechanism for one such cluster, named cluster 1082B, located on chromosome 7 in the mouse genome, containing 788 unique piRNAs. The precursor transcript and individual piRNAs within the cluster are repressed by the Alkbh1 dioxygenase and the transcription repressor Tzfp, which are believed to be interaction partners in testis. We observe more than a thousand-fold upregulation of individual piRNAs in pachytene spermatocytes isolated from Alkbh1-/- and TzfpGTi/GTi testes. Repression is further supported by the identification of a 10 bp Tzfp recognition sequence contained within the precursor transcript. Downregulation of long interspersed elements 1 (LINE1) and intracisternal A-particle (IAP) transcripts in the Alkbh1-/- and TzfpGTi/GTi testes leads us to propose a potential role for the 1082B-encoded piRNAs in transposon silencing. Overall design: Characterization of small RNAs in mouse pachytene spermatocytes for wild-type (WT) and Alkbh1-/- and TzfpGTi/GTi, and mRNA in mouse pachytene spermatocytes for wild-type (WT) and Alkbh1-/-
Alkbh1 and Tzfp repress a non-repeat piRNA cluster in pachytene spermatocytes.
Specimen part, Subject
View SamplesDeficiencies in the ATM gene are the underlying cause for ataxia telangiectasia, a congenital syndrome characterized by neurological, motor and immunological defects, as well as a predisposition to cancer risks. MicroRNAs (miRNAs) are small regulators of post-transcriptional gene expression and a useful tool for cancer diagnosis, staging, and prediction of therapeutic responses to clinical regimens. In particular, miRNAs have been used to develop signatures for breast cancer profiling. We are interested in the consequences of ATM deficiency on miRNA expression in breast epithelial cells and the potential contribution to cancer predisposition. In this study we investigate the effects of ATM loss on the miRNA expression and related gene expression changes in normal human mammary epithelial cells (HME-CC). We have identified 81 significantly differently expressed miRNAs in the ATM-deficient HME-CCs using small RNA sequencing. Many of these differentially expressed miRNAs have been described and implicated in tumorigenesis and proliferation. These changes include down-regulation of tumor suppressor miRNAs, such as hsa-miR-29c and hsa-miR-16, as well as the over-expression of pro-oncogenic miRNAs hsa-miR-93 and hsa-mir-221. All 81 miRNAs were combined with genome wide gene expression profiles to investigate possible targets of miRNA regulation. We identified messenger RNA (mRNA) targets of these miRNAs that were also significantly regulated after the depletion of ATM. Predicted targets included many genes implicated in cancer formation and progression, including SOCS1 and the proto-oncogene MAF. Integrated analysis of miRNA and mRNA expression allows us to build a more complete understanding of the pathways and networks involved in the breast cancer predisposition observed in individuals deficient in ATM. This study highlights miRNA and predicted mRNA target expression changes in ATM-deficient HME-CCs and suggests a mechanism for the breast cancer-prone phenotype seen in ATM deficient cells and patients. Additionally, this study provides preliminary data for defining miRNA profiles that may be used prognostic biomarkers for breast cancer predisposition. Overall design: Examination of small RNA population in human mammary epithelial cell lines. Each condition was preformed in triplicate.
Genome-wide small RNA sequencing and gene expression analysis reveals a microRNA profile of cancer susceptibility in ATM-deficient human mammary epithelial cells.
Specimen part, Cell line, Subject
View SamplesThe rate of transcription elongation plays important roles in the timing of expression of full-length transcripts as well as for the regulation of alternative splicing. In this study we coupled Bru-Seq technology with 5,6-dichlorobenzimidazole 1-ß-D-ribofuranoside (DRB) to estimate the elongation rates of over 2,000 individual genes in human cells. This technique, BruDRB-Seq, revealed gene-specific differences in elongation rates with a median rate of around 1.5 kb/min. We found that genes with fast elongation rates showed higher densities of H3K79m2 and H4K20me1 marks compared to slower elongating genes. Furthermore, fast elongation rates had a positive correlation with gene length, low complexity DNA sequence and distance from nearest active transcription unit. Features that negatively correlated with elongation rate included exon density and the number of LINE sequences in the gene. The BruDRB-Seq technique offers new opportunities to interrogate mechanisms of regulation of transcription elongation. Overall design: Measurement of RNA Pol II elogation rate. Normal fibroblasts (HF1 and TM), Cockayne syndrome group B fibroblasts, K562 and MCF-7 cells were exposed to DRB for 60 minutes, after which a washout was performed. Nascent RNA was labeled using bromouridine for 10 minutes immediately after the washout. The genomic region extending from actice Trancription Start Sites was used to determine the gene''s elongation rate. Please note that the nf_0h_3* samples are duplicated sample records of GSM1062445 and GSM1062446, for the convenient retrieval of the complete raw data from SRA.
Rate of elongation by RNA polymerase II is associated with specific gene features and epigenetic modifications.
No sample metadata fields
View SamplesSecond-hand smoke (SHS) exposure during pregnancy has adverse effects on offspring. We used microarrays to characterize the gene expression changes caused by in-utero exposure and adult exposure to SHS in adult mouse lungs.
In utero exposure to second-hand smoke aggravates adult responses to irritants: adult second-hand smoke.
Sex, Age, Specimen part, Treatment
View SamplesSHS exposure during pregnancy has adverse effects on offspring.
In utero exposure to second-hand smoke aggravates the response to ovalbumin in adult mice.
Sex, Specimen part
View SamplesThe objective of this set of samples is to identify genes that are differentially expressed following the introduction of DNA double strand breaks (DSBs) by ionizing radiation in wild-type murine pre-B cells. The data generated in this project will be compared to the data generated in GSE9024, in which genes that are differentially expressed following the introduction of DNA double strand breaks (DSBs) by the Rag proteins in murine pre-B cells were examined. In order to understand the differences between the physiologic and genotoxic responses to DSB DNA damage, we need to compare cells that are all in the same compartment of the cell cycle. We are therefore examining the response to IR-induced damage in cells that are arrested in G1, which would correspond to our previous study of G1 arrested cells with Rag-induced breaks. This will illuminate the difference directly, allowing us to better understand the signaling responses to the different types of DNA damage.
DNA damage activates a complex transcriptional response in murine lymphocytes that includes both physiological and cancer-predisposition programs.
Specimen part
View SamplesThe objective is to identify genes that are differentially expressed following the introduction of DNA double-strand breaks (DSBs) by the Rag proteins in murine pre-B cells. Cells lacking Artemis are used since the Rag-induced DSBs will not be repaired, and thus, will provide a continuous stimulus to the cell.
DNA damage activates a complex transcriptional response in murine lymphocytes that includes both physiological and cancer-predisposition programs.
Specimen part, Disease, Treatment
View SamplesWe recently isolated and identified (7E)-9-oxohexadec-7-enoic acid (1) and (10E)-9-oxohexadec-10-enoic acid (2) from the marine algae Chaetoceros karianus. Synthesis and biological characterization show that these are PPARa/? dual agonists. Herein we report the gene expression data from human SGBS pre-adipocytes, stimulated to differentiate with 1, 2 or the classical PPAR? agonist rosiglitazone. The transcriptome analysis shows that both compounds induce anti-diabetic gene programs in adipocytes by upregulating insulin-sensitizing adipokines and repressing pro-inflammatory cytokines. Overall design: Human SGBS pre-adipocytes were stimulated with adipogenic media supplemented with either (7E)-9-oxohexadec-7-enoic acid, (10E)-9-oxohexadec-10-enoic acid, or rosiglitazone from day 0 to day 4. On day 4, agonists were withdrawn, and the cells were allowed to differentiate following standard protocol. On day 8, RNA was isolated and sent to sequencing.
Synthesis and biological evaluations of marine oxohexadecenoic acids: PPARα/γ dual agonism and anti-diabetic target gene effects.
Specimen part, Cell line, Subject
View SamplesThe use of calcineurin inhibitor (CI) immunosuppressants has significantly improved the early allograft survival rate in organ transplantation. However, CI therapy has been associated with chronic nephrotoxicity, which limits their long-term utility. In order to understand the mechanisms of the toxicity, we analyzed the gene expression changes that underlie the development of CI immunosuppressant-mediated nephrotoxicity, in male Sprague-Dawley (SD) rats dosed daily with cyclosporine (CsA), FK506 or rapamycin (Rapa) for 1 to 28 days. We identified a group of genes, whose expression in rat kidney is quantitatively correlated with CI-induced kidney injury as observed in changes in blood urea nitrogen (BUN) levels and kidney histopathology. These genes include both up-regulated genes, such as Ren1 and Klks3, and down-regulated genes, such as Calb1, Egf, NCC, and kidney specific Wnk1 (KS-Wnk1). Using the down-regulated genes alone we successfully predicted CI immunosuppressant-mediated kidney injury in rats following 7 days of treatment. Among these genes are two mechanism-related genes, NCC and KS-Wnk1, both of which are involved in the sodium transport in the distal nephrons. The down-regulation of both genes at the mRNA and protein level in rat kidney following CI treatment was confirmed by quantitative RT-PCR and immunohistochemical staining, respectively. We hypothesize that decreased expression of NCC may cause reduced sodium chloride reabsorption in the distal tubules, and contribute to the prolonged activation of the Renin-Angiotensin-System (RAS), a demonstrated contributor to the development of CI-induced nephrotoxicity in both animal models and clinical settings. Therefore, NCC and KS-Wnk1 could potentially be used as biomarkers for early detection and prevention of CI-related nephrotoxicity in clinical practice.
Genomic-derived markers for early detection of calcineurin inhibitor immunosuppressant-mediated nephrotoxicity.
Sex, Specimen part
View SamplesThe use of radiation treatment has increased for both sporadic and neurofibromatosis type 2 (NF2)-associated vestibular schwannoma (VS). However, there are a subset of radioresistant tumors and systemic treatments that are seldom used in these patients. We investigated molecular alterations after radiation in three NF2-associated and five sporadically operated recurrent VS after primary irradiation. We compared these findings with 49 non-irradiated (36 sporadic and 13 NF2-associated) VS through gene-expression profiling and pathway analysis. Furthermore, we stained the key molecules of the distinct pathway by immunohistochemistry. A total of 195 differentially expressed genes in sporadic and NF2-related comparisons showed significant differences based on the criteria of p value < 0.05 and a two-fold change. These genes were involved in pathways that are known to be altered upon irradiation (e.g., mammalian target of rapamycin (mTOR), phosphatase and tensin homolog (PTEN) and vascular endothelial growth factor (VEGF) signaling). We observed a combined downregulation of PTEN signaling and an upregulation of mTOR signaling in progressive NF2-associated VS after irradiation. Immunostainings with mTOR and PTEN antibodies confirmed the respective molecular alterations. Taken together, mTOR inhibition might be a promising therapeutic strategy in NF2-associated VS progress after irradiation.
Contribution of mTOR and PTEN to Radioresistance in Sporadic and NF2-Associated Vestibular Schwannomas: A Microarray and Pathway Analysis.
Specimen part, Disease
View Samples